Study on Solvent Circulation on Co-liquefaction of Woody Biomass and Plastics

Abstract

Because the re-use of the solvent is difficult in solvent circulation type direct liquefaction process of woody biomass, the authors examined the possibility of solvent supply from plastic and the degradative behavior of the initial solvent under the condition of co-liquefaction of woody biomass and plastic. In the present study, Japanese cedar was used as woody biomass, polypropylene, polyethylene, and polystyrene, as model waste plastics and mineral oil as initial solvent. The effect of the reaction temperature on its performance and possibility of solvent circulation have been investigated and the following results were obtained. Because the decomposition of the mineral oil occurs in the reaction temperature higher than 400 °C because of the interaction with the biomass and plastics, that lower than 400 °C is preferable. The decomposition of plastics is promoted by the interaction caused by the co-liquefaction and yield of solvent fraction increases, excluding the polystyrene. Because the decomposition of the mineral oil occurred when the mineral oil was used as the initial solvent, the amount of solvent fraction was not sufficient after the reaction and the solvent circulation was difficult. It is expected that this problem can be solved by adjusting the polar compound fraction in the initial solvent.